A polycarbonate resin is excellent in the mechanical strength, the electrical properties, the transparency and the like, and is widely used as an engineering plastic in various fields such as electric and electronic equipment fields and automobile fields. In recent years, in such application fields, reduction in thickness, downsizing and weight saving of molded articles are in progress, and further improvement in the performance of materials to be molded is required. However, a conventional polycarbonate resin made of bisphenol A as a raw material has not necessarily been sufficiently excellent in the surface hardness. Accordingly, development of a polycarbonate resin having a high surface hardness has been desired, and several proposals have been made.
For example, Patent Documents 1 and 2 propose a method for producing a polycarbonate or a copolycarbonate excellent in the surface hardness by using a bisphenol different from bisphenol A as a monomer. However, by this method, even though a polycarbonate resin composition excellent in the surface hardness is obtained, it is necessary to sacrifice other physical properties.
Further, Patent Document 3 proposes a method of bonding different types of polymers on a molded specimen such as hard coating treatment, to form a multilayered structure. However, this method has such a problem that the shape of the molded article is limited to a sheet shape or the like, and the application is limited. Further, it has drawbacks of low productivity such that the number of steps increases so as to achieve a multilayered structure, a complicated treatment is required at the time of molding, and defective articles are molded at the time of hard coating.
Further, Patent Document 4 proposes to improve the surface hardness of a blended material of a polycarbonate resin derived from dimethyl bisphenol cyclohexane and a bisphenol A type polycarbonate resin.